Heat management can be critical in many applications. Excessive heat can cause damage to or degrade the performance of mechanical, chemical, electric, and other types of devices. Heat management becomes more critical as technology advances and newer devices continue to become smaller and more complex, and as a result run hotter.
Modern electronic circuits, because of their high density and small size, often generate a substantial amount of heat. Complex integrated circuits (ICs), especially microprocessors, generate so much heat that they are often unable to operate without some sort of cooling system. Further, even if an IC is able to operate, excess heat can degrade an IC's performance and can adversely affect its reliability over time. Inadequate cooling can cause problems in central processing units (CPUs) used in personal computers (PCs), which can result in system crashes, lockups, surprise reboots, and other errors. The risk of such problems can become especially acute in the tight confines found inside laptop computers and other portable computing and electronic devices.
Prior methods for dealing with such cooling problems have included using heat sinks, fans, and combinations of heat sinks and fans attached to ICs and other circuitry in order to cool them. However, in many applications, including portable and handheld computers, computers with powerful processors, and other devices that are small or have limited space, these methods may provide inadequate cooling.
In particular, cooling devices mounted on the bottom of a motherboard present a more acute problem. Typically, there is less room between the bottom face of the mother board and the bottom skin of a portable computer (i.e., notebook computer). As a result, it becomes difficult to fit a device on the underside of the motherboard to reduce the temperature of heat generating devices mounted to the underside of the motherboard. Furthermore, mounting heat generating devices to the underside of the motherboard also creates the undesirable effect of sometimes generating a hot spot on the bottom skin of the notebook computer, further creating the need to reduce the temperature of the heat generating devices mounted on the bottom side of a motherboard. Hot spots on the bottom skin of a notebook computer are becoming even more commonplace today as the skin of notebooks are becoming ever thinner.
One possible solution to reduce the temperature of the heat generating devices mounted on the bottom side of a motherboard is illustrated in FIG. 1. As illustrated in FIG. 1, a fan 102 may be placed on a side of the motherboard 104 to generate a flow of air across a top side and bottom side of the motherboard to cool components 106 mounted on both sides of the motherboard. However, such a thermal solution takes away from the capability to cool heat generating devices mounted on the top side which create relatively larger amounts of heat (e.g., central processing units). Futhermore, the use of fans also creates undesirable noise.